This invention relates in general to a drum brake assembly and, in particular, to an improved operating mechanism which can effectively be used in a drum-in-hat parking and emergency brake assembly of a hydraulic disc brake.
In most vehicle designs, the drum brake assembly includes a parking and emergency brake actuation cable which is oriented generally parallel to a backing plate of the brake assembly or perpendicular to an axle of the vehicle. However, in some vehicle designs, due to the arrangement of various components, it is not possible to orient the parking and emergency brake actuation cable parallel to the backing plate. In these instances, it is known to provide a drum brake assembly with a parking and emergency brake actuation cable which is oriented generally perpendicular to the backing plate or parallel to the axle of the vehicle.
One example of a drum brake assembly having a parking and emergency brake actuation cable oriented in this manner is disclosed in U.S. Pat. No. 4,018,312 to Muramoto et al. As shown in this patent, the parking and emergency brake actuation cable is oriented generally perpendicular to the backing plate of the brake assembly so as to avoid interference with rear suspension elements of the vehicle. The cable is connected to a four-joint link assembly which is operative to engage and actuate the brake shoes when the cable is actuated.
Other examples of drum brake assemblies having a parking and emergency brake actuation cable oriented generally perpendicular to a backing plate of the brake assembly are disclosed in U.S. Pat. No. 3,870,131 to Firth et al., U.S. Pat. No. 3,023,853 to Nawrot, U.S. Pat. No. 2,259,266 to Rabe, and U.S. Pat. No. 2,006,494 to Bendix et al.